Tennis racket



Jly, 1928. l R.. H. kFaoBlNscaN TENNIS RAC'KET orumawiled Dec. 15, 1923Patented July 3, 1928.

UNITED STATES ROY E. ROBINSON, 0F CHICAGO, ILLINOIS.

TENNIS RACKET.

Application led December 15, 1923, Serial No. 680,956. Renewed September8, 1927.

This invention relates to tennis rackets but more particularly to suchas are provided with a metal frame and has for its primary -obj'ect toeliminate the cutting of the Stringing by the frame.

It has been found in practice that gut stringing cannot be used withmetal frame rackets asnow produced because the metal quickly cuts thegut. These rackets have therefore been generally strung with Wire whichdoes not possess the resiliency of gut, and even wire soon breaks. Theseframes are made of light gauge metal tubing which is punched for theStringing and then bent into proper form. The punched holes are made assmooth as possible but the strings come in Contact with these edges andare cut thereby. This cutting is accelerated by the movement of thestrings when the racket is in use.

In my improved racket the advantages of the metal frame are fullyretained but the cutting of the Stringing is eliminated and gut may beused as well as in a woodenrame racket.

The many other objects and advantages of my invention will be betterunderstood by reference to the following specification when consideredin connection with the accompanying drawing illustrating certainselected embodiments thereon, in which Fig. 1 is a plan View of aracket.

Figs. 2 to 4 are transverse sections of the frame illustrating onemethod of construction.

Fig. 5 illustrates a further step in the formation of the racket frame.

Fig. 6 is a longitudinal section of a portion of' a complete frame.

F 1'gs 7 and 8 are transverse sections of modified forms of frameconstruction, and

Fig. 9 is a perspective view of a section of a modified form of frame.

Referring to the drawing and particularly Figs. 1 to 5, the racketcomprises a frame 10, handle 11 and Stringing 12. The frame in thepresent embodiment comprises a tube 9 which is bent into substantiallyoval form, as at 13, with the ends of the tube turned outwardly, as at14, and inserted into the handle. The portions 14 of the tube form whatis ltermed the throat of the racket. A strut or spreader 15 is providedat the throat. This strut forms a portion of the frame to receive theStringing. The particular design of racket frame illustrated in Fig. 1is similar to that made by a wellknown manufacturer. The handle l11 isof wooden construction and a metal ferrule 16 envelops and supports theforward end thereof.

In my improved construction the metal tube 9 and the strut 15 are eithercompletely or partially filled with a non-metal substance as at 18. Avariety of substances may be used for this one which will not absorbmoisture and consequently will not warp. A plastic molded mass such asvulcanized fiber thor- \oughly impregnated with a combination of phenoland formaldehyde, and then hardened by heating. Such material is plasticand has high compressive strength and relatively high tensile strength.`Very satisfactory results have been obtained by the use of leather, rawhide, or ordinary hard fiber and other substances of a similarcharacter. This filled tube may be manufactured in a variety ofdifferent ways, one of which is illustrated in Figs. 2 to 4 inclusive.By this method the filler material 18 is driven into the round tube 9 asin. Fig. 2. The filled tube is then punched for the stringing. In thefirst punching operation a series of oppositely disposed relativelylarge holes 19 are punched in the metal shell without materiallypenetrating the filler, but partially penetrating the same, as in Fig.3. This causes the tube to assume a somewhat oval cross-section. Theinwardl -turned edge 2O produced by the punching 1s forced into thefiller and thus becomes permanently embedded therein. The next ste is todrill or otherwise drive a seria o relatively small holes 21 through thefiller, these holes 21 being substantiall concentric with thecorresponding large oles 19 in the metal tube (Figs. 4 to 6). The edgesof the small holes 21 are preferably slightly rounded or chamfered toprovide a rounded bearing surface for the strings. The punched tube maythen be assed between compressing rolls as 17 to fiirther flatten thesame as 1s illustrated in Fig. 5. This is advantageous as it tends tofurther force the punch-hole edges into the filler. This step can eitherprecede or follow the drilling of the filler. The small holes in thefiller may obviously be provided before it is inserted in the metaltubing and this is perferable where the filler is composed of hardfiber.

In Fig. 7 is illustrated a frame which is purpose but I preferrectangular in cross-section instead of round or oval. This is punchedor slotted in the same manner as the round or oval tube.

Instead of inserting the filler in the unpunched tube and then punchingthe tube in the manner described, the tube may be punched and thevfiller subsequently inserted. This is accomplished by usingv a fillerof a thickness to permit it to be pushed into the tube between theprotruding edges of the punched holes. The tube may then be compressedby means of rollers to cause the edges to be embedded in the filler.Such a construction is illustrated in F ig. 8 of vthe drawing, the metaltube being designated 25 and the filler 26.

In Fig. 9 of the drawing is illustrated a modified form of frameconstruction which primarily consists of a metal shell vas 80 and afiller as 31. This shell is not in tubular form but is made by bending astrip of sheet metal in the form indicated with the edges 32 of thestrip turned inwardly and fitting within corresponding slits or grooves83 in the previously formed filler. In this construction a reinforcingplate, as 34, may be interposed between the top or outer wall 35 of theshell and the corresponding wall of the filler. The strip andreinforcement are preferably provided with a series of perforations orslots, as 36 and 37, before being bent. The filler is perforated forthestringing as at 38, these perforations being considerably smaller thanthe corresponding perforations 36 and 87 inthe shell and reinforcement.

It will be evident from the foregoing description that the Stringing inmy improved socket is held away at all times from 'metal edges by thefiller and can not be eut thereby. The metal bearing surfaces are smoothand rounded. The metal tube or shell may be made of thinl steel,aluminum alloy, nickel, or any other material possessing the necessarystrength and lightness.

'I am aware that the frame construction may be materially varied withoutdeparting from the spirit of my invention and I reserve the right tomake all such variations as fairly fall within the scope of thefollowing claims.

I claim yas my invention:

1. In a tennis racket, a frame comprising a tubular metal shell having aseries ofoppositely disposed perforations therein to receive Stringing,and string Guides of nonmetallic material within said shell, said stringguides projecting into said perforations to prevent the strings fromcontacting with the edges at said perforations in said metal shell.

2. In a tennis racket, a frame comprising a metal shell having a seriesof oppositely disposed perforations therein to receive Stringing, andStringing guides of non-meaevaoei metallic material Within said shellhaving string passages connecting the corresponding perforations in saidshell, said passages being substantially concentric with saidperforations and of smaller cross-sectional area, said string guidesprojecting into said perforations whereby the strings are prevented fromcontacting with the edges of the metal at said perforations.

4. In a tennis racket, aframe comprising a tubular metal shell having aseries of oppositely disposed perforations therein to receive Stringing,and string guides of fibrous material within said shell, said fibrousmaterial projecting into said perforations whereby the strings areprevented from contacting with the edges of the metal at saidperforations.

5. In a tennis racket, a frame comprising a metal shell having Stringingholes formed therein, and a strip of non-metallic material extendinglongitudinally within said shell, the turned-in metal edges of the shellproduced by the forming of the holes therein being partially embedded insaid strip.

6. In a tennis racket, a frame comprising a metal shell havingrelatively large stringing holes formed therein, and a strip ofnonmetallic material extending longitudinally within said shell andprovided with stringing passages communicating with the correspondingholes in said shell and of smaller cross-sectional area than said holes,the edges of the holes being formed with turnedin portions embedded insaid strip.

7. In a tennis racket, a frame comprising a metal shell having.Stringing holes punched therein, and a fibrous filler extendinglongitudinally within said shell and having stringing passagesconnecting the corresponding holes in said shell, the turned-in metaledges of the shell produced by the punching of said holes beingpartially embedded in said filler.

8. In a tennis racket, a frame comprising a thin metal shell havingStringing perforations therein, and filler of non-metallic materialwithin said shell provided with stringing perforations communicatingwith the corresponding perforations in said shell, the material of thefiller projecting into perforations in the shell.

9. In a racket, a frame comprising a tubular metal shell, a cushioningfiller Within the shell, there being Stringing passages extendingthrough said yshell and filler, and strings passing therethrough, theedges of the shell at the passages being in contact with the filler toprevent exposure and contact thereof With the strings except at thefiller to4 thereby prevent cutting of the strings.

l 10. In a racket, a frame comprising a tubular metal shell, a moistureproof filler Within said shell, stringing passages extending throughsaid shell and filler and strings passing therethrough, the edges ot themetal at the passages in the shell being rounded to dispose the stringsout of contact with the edges and prevent cutting of the stringsthereby.

1l. In a racket, a frame comprising a tubular metal shell, amoisture-proof ller Within said shell, Stringing passages extendingthrough said shell and filler and strings passing therethrough, thepassages in the shell being formed With inturned edges,

and said edges being embedded lin said filler to prevent cutting of thestrings thereby.

12. In a racket, a frame portion having a stringing hole with anon-metallic stringcontacting portion and an easy bearing faceapproaching the non-metallic string-contacting portion and being free ofsharp edges.

13. In a racket, a string support having a Stringing hole With anon-metallic string contacting portion combined With a metallic easybearing face approaching the nonmetallic stringcontacting portion.

14. In a tennis racket` a frame comprising a tubular metal shell and anon-moisture absorbing iller Within said shell which consists of plasticmaterial of high compressive strength and relatively high tensilestrength.

15. In a racket, a frame comprising a tubular shell, a moisture-proofiller; Within said shell, there being Stringing passages extendingthrough said shell and filler and strings passing therethrough, theedges of the shell at the passages being rounded and turned outwardly attheir inner ends to dispose the strings out of contact with the shelland prevent cutting of the strings thereby.

16. In a racket, a frame comprising a tubular metal shell, a filler ofhigh compressive strength and relatively high tensile strength Withinsaid shell, there being Stringing passages extending through the shelland iller and strings passing therethrough, the edges of the metal atthe passages in the shell being rounded and enlarged with respect to thepassages of the filler which receive the strings to dispose them out ofcontact with the metal and prevent cutting of the strings thereby.

17. In a racket, a. frame comprising a shell, a cushioning andvibration-absorbing filler Within the shell, there being Stringingpassages extending through the shell and filler, and strings passingtherethrough, the edges of the shell at the passages being Covered bythe filler and the passages of the filler being restricted to preventContact 0f the strings with the edges of the shell at the passagestherein and cutting of the strings thereat.

18. In a racket, a frame comprising a tubular metal shell, anon-metallic cushioning and vibration absorbing or dampening fillerWithin the shell, the edges of the shell at the passages engaging theliller around its passages to prevent cutting of the strings.

19. In a tennis racket, a frame comprising a tubular metal shell, astrip of nonmetallic cushioning and vibration dampening materialextending longitudinally within said shell and substantially filling thesame, and Stringing passages extending through said shell and said stripand disposed to hold the strings out of contact with the shell or edgesthereof at the passages.

20. In a tennis racket, a frame comprising a metal shell, a strip ofnon-metallic cushioning and vibration dampening material extendinglongitudinally Within said shell, and stringing passages extendingthrough said shell and said strip, the material of the shell beingturned in at the passages to contact with the strip so that the stringscontact only with the strip in the passages and prevent contact of thestrings with the edges of the metal shell at the passages.

21. A racket frame having a metal exterior facing secured to or joinedWith a filler member, with inturned edges projecting into said filler.

22. A racket frame having a metal exterior face secured to a fillermember, with inturned portions projecting into said filler, the fillerhaving openings for receiving Stringing and t-he face having edgeportions protected by the ller Where the strings extend therethrough.

23. A metal racket frame having an inner and an outer face of metal witha nonmetallic filler held rigidly between said metal faces, Stringingholes formed in the metal faces, and non-metallic filler in said holes.

24. A metal racket frame having an inner and an outer face of met-alwith a nonmetallic liller held rigidly between said metal faces, andStringing holes formed in the metal faces, the edges of the metal at theholes being pressed against the filler to protect the same from contactof the edges of the metal with the Stringing at the holes.

25. In a tennis racket, a frame comprising a tubular shell and Stringingpassages extending through said shell, the passages having cushioningguides extending up into perforations or passages of the shell.

26. A metal tennis racket frame with Stringing holes of a substantialdepth formed therein and non-metallic material so disposed in relationto the Stringing holes as to prevent strings contacting with any cuttingedges of the metal holes regardless of what angle the strings take inpassing out of the holes, and the frame having an easy bearing faceWherever contacting with the Stringing.

27. A metal tennis racket frame combined with a non-metallic cushioningmember, both having -stringing holes, strings passing through theStringing holes formed in both, the Stringing holes in the non-metallicmember being smaller than the corresponding ones in the metal frame, andthe holes in the metal frame being rounded or `chamfered and marginedback from the non-metallic holes.

28. A tennis racket having a metal frame combined with a non-metallicmember and Stringing passing through said frame and non-metallic memberand so disposed as to bear against the non-metallic member withoutcontacting with any cutting edges of the sti-inging holes of the metalframe and to contact with an easy bearing face of the metal.

29. In a. tennis racket frame formed of a metal shell and a non-metallicvmaterial within, the non-metallic material being held in place byturned-in edges of the metal at i the Stringing holes formed in a faceof the shell. f

30. A metallic tennis racket frame having a tubular cross section withinterior shock absorbing material, the shock absorbing material beingheld in position by turned-in edges of stringing holes formed in thetube.

31. A tennis racket frame having stringing and a metal outer Walltransverse to the plane of the Stringing, a non-metallic element bearingon the lnner face of said wall,

the Stringing contacting with the metal on the outer face of said metalwall and bearing against the non-metallic element, the non-metallicelement protecting the strings from'any cutting edges of the metal Wall.

32. A tennis racket frame having stringing holes and Stringing passingthrough lthe same and a metal outer Wall transverse to the plane of theStringing, a non-metallic clement bearing on the inner face of saidwall, the Stringing contacting with the metal on the outer face of saidmetal Wall and bearing against the non-metallic element, thenon-metallic element protecting the strings from any cutting edges ofthe metal Wall, and a non-metallic cushioning element also in the holesof the metal Wall.

33. A tennis racket comprising a tubular frame' having Stringing holesin oppositev Walls and string cushioning material Within the tube andthe tubebeing crushed against the cushioning material.

34. A tennis racket comprising va shell having Stringing holes withturned-in edges and a Filling material between said turnedin edges.

35. A tennis racket having a frame formed of a shell with Stringingholes formed in the shell thereof and a non-string cutting materialwithin the shell covering the cutting edges of the shell at the holes.

36. In a tennis racket, a metallic frame having Stringing passages insame and the passages having non-metallic cushioning guides therein toreceive .the Stringing and forming non-abraiding and non-cuttingbearings therefor.

ROY H. ROBINSON.

